1. Field of the Invention
The present invention relates to an analysis apparatus utilizing an electrophoresis process, for example.
2. Description of Related Art
To analyze a specimen for quantitating the concentration or amount of a specific component contained, an analysis method based on a capillary electrophoresis process is widely employed. In the capillary electrophoresis process, an electrophoretic liquid is loaded in a separation channel having a relatively small cross-sectional area, and the specimen is introduced into the separation channel from an end portion thereof. Then upon applying a voltage to both ends of the separation channel, the electrophoretic liquid flows from the anode toward the cathode, thereby generating an electro-osmotic flow. At the same time, the specific component of the specimen is driven to move in accordance with its electrophoretic mobility, by the applied voltage. Accordingly, the specific component migrates as expressed by a velocity vector generated by merging the velocity vector of the electro-osmotic flow and the velocity vector of the electrophoretic movement. As a result, the specific component is separated from other components of the specimen. Then the amount and concentration of the specific component can be analyzed by detecting, for example by an optical method, the specific component thus separated.
FIG. 13 depicts a conventional analysis apparatus. The analysis apparatus X shown therein includes a microchip 91 and a voltage applier 92. An introduction tank 911, a drain tank 913, and a separation channel 912 communicating between these tanks are provided on the microchip 91. An electrophoretic liquid is loaded in the introduction tank 911 and the separation channel 912 in preparation for the analysis. A specimen S, the object of the analysis such as blood, is stored in a specimen container B. The specimen S is introduced into the introduction tank 911 through an introduction nozzle 93. The voltage applier 92 includes a power source 921 and electrodes 922, 923. To perform the analysis, the electrode 922 is soaked in the introduction tank 911 and the electrode 923 is soaked in the drain tank 913. Upon applying a predetermined voltage between the electrodes 922, 923, a specific component of the specimen S starts to be separated by electrophoresis. A light emitter 941 and a light receptor 942 are disposed halfway of the separation channel 912, so as to oppose each other across the separation channel 912. To the light emitter 941, a light source 943 supplies a light. The light receptor 942 is connected to a detector 944. Thus, the concentration of the specific component of the specimen S can be measured by measuring for example the absorbance of the specimen S by the detector 944.
However, once an analysis process is performed, the specimen S sticks to the electrode 922. Also, as a result of applying a voltage for the electrophoresis, the components of the specimen S and electrophoretic liquid are deposited on the electrode 922. Utilizing again the electrode 922 under such a condition for subsequent analysis processes may allow different specimens to be mixed, or allow the deposited components to be mixed in the specimen for the subsequent analysis processes. To prevent such situations, the operator has to assume a burden of manually replacing the electrode 922 prior to each analysis process, which makes the operation inconvenient and inefficient.